Because LGLL has continuously activated cytotoxic T lymphocytes, immunosuppressive therapy is the standard first-line therapy for T-LGLL and CLPD-NK. Previous studies showed that the overall response rate (ORR) of first-line oral immunosuppressants ranged from 21% to 85% (median: 50%). Both methotrexate and cyclosporine A are LGLL first-line treatment options, but the CR rate of methotrexate is only 21%, while the CR rate of CsA is less than 5%. There is insufficient evidence for the treatment of LGLL with prednisone and other glucocorticoids, but it can reduce RA-related inflammation and increase granulocyte levels. The TPM regimen was designed by the investigators. A pilot prospect observation showed that 18/20 (90%) patients obtained response, including 80% CR. This study is a prospective multiple center clinical trail to evaluate the efficacy of TPM regimen in the treatment of symptomatic LGLL. Eligible patients choose the initial treatment plan: thalidomide 50-100mg qn+ prednisone 0.5-1mg / kg qod +methotrexate 10mg / m2 / week. Four months is one course. Maximum three courses will be given if there is a response and thalidomide maintenance will be for another year.